Method for improving cross-type frequency selective surface

A new cell structure is proposed based on the conventional cross-shaped patch of frequency selective surface, which can reduce the -20dB stopband from 0.56GHz to 0.32GHz (with the decreasing amplitude of 42.9%) under the normal incidence by transverse electric (TE) wave. Hence, the frequency-selective characteristic was improved. Meanwhile, the interesting advantage of this method is that it does not need to change the size of the original frequency selective surface to achieve an effective promotion of the frequency-selective characteristics of the entire unit, and compared to the resonance frequency of the original structure, the frequency drift is only about 0.05GHz. Finally, the structure sample is fabricated, and measured results and simulation by HFSS are presented and agree well to verify the correctness of the proposed method.